The proposed studies fall into five categories: 1) the role of prostaglandin in regulating uterine and fractional distribution of intracortical renal blood flow, 2) a possible role for plasma prostaglandin in regulating effective blood volume in edematous states, i.e. cirrhosis, nephrosis, congestive heart failure, and in pregnancy, 3) renal prostaglandin E secretion will be studied in humans with renal hypertension with and without intact kidneys, 4) renal venous and urinary prostaglandin will be determined during natriuresis to investigate its possible role as a natriuretic substance of physiological importance, 5) studies of jejunal sodium transport in various models of sodium balance will be undertaken to determine if epithelial sodium transport in jejunum has any similarity to renal sodium transport.